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/* Copyright (C) 1999-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#define _ERRNO_H 1
#include <bits/errno.h>
/* Clone the calling process, but without copying the whole address space.
The calling process is suspended until the new process exits or is
replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
and the process ID of the new process to the old process. */
ENTRY (__vfork)
/* Save the TCB-cached PID away in w3, and then negate the TCB
field. But if it's zero, set it to 0x80000000 instead. See
raise.c for the logic that relies on this value. */
mrs x2, tpidr_el0
sub x2, x2, #PTHREAD_SIZEOF
ldr w3, [x2, #PTHREAD_PID_OFFSET]
mov w1, #0x80000000
negs w0, w3
csel w0, w1, w0, eq
str w0, [x2, #PTHREAD_PID_OFFSET]
mov x0, #0x4111 /* CLONE_VM | CLONE_VFORK | SIGCHLD */
mov x1, sp
DO_CALL (clone, 2)
/* Restore the original value of the TCB cache of the PID, if we're
the parent. But in the child (syscall return value equals zero),
leave things as they are. */
cbz x0, 1f
str w3, [x2, #PTHREAD_PID_OFFSET]
1:
cmn x0, #4095
b.cs .Lsyscall_error
RET
PSEUDO_END (__vfork)
libc_hidden_def (__vfork)
weak_alias (__vfork, vfork)
strong_alias (__vfork, __libc_vfork)
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